Hydraulic Unit and Control Units for Hydraulic Brake Systems

ABSTRACT

In a hydraulic unit, which is for a hydraulic brake system, that has a hydraulic block and at least one valve device, the valve device includes a hydraulic cartridge with a valve seat and with a movable closing body for blocking and opening the valve seat, and a magnet assembly with a magnet coil for generating a magnetic force for moving the closing body. The magnet assembly is integrated into the hydraulic block, and the valve device has a permanent magnet in order to assist the movement of the closing body by means of magnetic force.

The invention relates to a hydraulic unit for a hydraulic brake systemwith a hydraulic block and at least one valve apparatus, the valveapparatus comprising the following elements: a hydraulic cartridge witha valve seat and with a displaceable closing body for blocking andreleasing the valve seat and a magnet assembly with a solenoid forgenerating a magnetic force for displacing the closing body, wherein thehydraulic unit is characterized in that the magnet assembly isintegrated into the hydraulic block and the valve apparatus has apermanent magnet in order to support the displacement of the closingbody by means of magnetic force.

PRIOR ART

For example, patent application DE 101 04 875 A1 is known from the priorart. This publication relates to a The invention relates to a hydraulicassembly for slip-controlled brake systems of motor vehicles with avalve block with receiving bores for in each case a hydraulic part ofelectromagnetically activated valves which include in each case a valvedome which contains magnetically active elements such as an armature anda magnetic core of the hydraulic part and in each case an electric partwhich is pushed onto the valve dome and has an electric coil whichencloses said valve dome, a coil housing as well as an annular discaccommodated at least indirectly in the coil housing on the side facingthe hydraulic part.

DE 33 05 833 A1 discloses a bistable solenoid valve which has an excitercoil and an armature which dips in it and which is composed of apermanent magnetic material, is polarized in its direction of movementand forms a valve seat. A magnetic field conducting body projects like acore into the exciter coil and fills a part of the length of the excitercoil.

A further magnetic field conducting body is arranged next to that end ofthe exciter coil into which the armature dips and is formed in the formof an annular disc which surrounds the armature with a spacing. In thecase of a deenergized exciter coil, forces act between these magneticfield conducting bodies and the armature which move the armature intolatching positions or at least hold them there and thus ensure stableswitching positions of the solenoid valve. In this solenoid valve, thereis no need for a spring which can bring the valve part into apredetermined latching position.

DISCLOSURE OF THE INVENTION

In contrast, the hydraulic unit according to the inventionadvantageously enables a very small overall installed size whilesatisfying the hydraulic requirements for ESP and assistance functions.

This is enabled according to the invention by the features indicated inthe independent claims. Further configurations of the invention are thesubject matter of subordinate claims.

The hydraulic unit according to the invention for a hydraulic brakesystem with a hydraulic block and at least one valve apparatus, thevalve apparatus comprising the following elements: a hydraulic cartridgewith a valve seat and with a displaceable closing body for blocking andreleasing the valve seat and a magnet assembly with a solenoid coil forgenerating a magnetic force for displacing the closing body ischaracterized in that the magnet assembly is integrated into thehydraulic block and the valve apparatus has a permanent magnet in orderto support the displacement of the closing body by means of magneticforce.

This refers to the hydraulic unit comprising at least the two structuralunits hydraulic block and valve apparatus. The valve apparatus (alsoreferred to as valve or solenoid valve) comprises the component groupsmagnet assembly and hydraulic cartridge. In this case, at least themagnet assembly is integrated into the hydraulic block. This means thatthe hydraulic block has an opening in which this component group can beaccommodated and integrated. It is not necessary for this purpose thatthe hydraulic block entirely encloses the component group. Rather,integration is to be understood such that the component group is locatedspatially within the volume block represented by the lateral surfaces ofthe hydraulic block. For example, the valve apparatus, installed flushwith the surface in a recess of the hydraulic block, can be regarded asintegrated therein. A functional integration can also be present inaddition to the spatial integration. A functional integration ischaracterized, for example, by functional interactions such as, forexample, thermal transmission or enabling fluid flows between thecomponents. The integration can of course also comprise a correspondingfrictional and/or positive connection.

The integration of valve apparatuses into the hydraulic block generallyleads, however, to a pronounced reduction in the available magneticforce. On one hand, this is due to the fact that the integrationrequires a small installation volume of the valves. The coil size, whichhas a direct influence on the magnetic force which can be generated, isalso affected by this. As a result of the integration of the coils intoa metallic housing such as the hydraulic block, there can also arise asignificant influence as a result of a weakening and/or disruption ofthe generated magnetic field. These effects have such a negativeinfluence on the power available for switching the valve or its speedthat hydraulic requirements for ESP systems and the driver assistancesystem can no longer be ensured.

The loss of power which arises in the case of a valve apparatusintegrated into the hydraulic block can, however, be compensated for bya permanent magnet positioned and installed at a suitable location. Forexample, the permanent magnet can be connected fixedly to the solenoidarmature in order to assist the movement of the solenoid armature. Forthis purpose, the permanent magnet can be introduced and/or sprayed onor cast into a recess on that end surface of the armature which facesthe pole core. Of course, the permanent magnet also has to be adapted tothe respective valve apparatus in terms of its size and type. Forexample, the permanent magnet can be configured to be disc-shaped.

The hydraulic brake system is, for example, a hydraulic brake system fora motor vehicle, in particular for a car or a motor bike. As a result ofthis, as already indicated, a magnetic loss of force can advantageouslybe avoided and thus the requirements for use in an ESP and assistancefunction are furthermore satisfied. The use of this valve design infuture systems is thus enabled. A small solenoid valve can be enabled asa result of the integration of a permanent magnet, for example, into thearmature. The integration of the valve apparatus into the hydraulicblock also has a number of other advantages in addition to the morecompact overall installed size of the hydraulic unit: for example, thehousing (i.e. the hydraulic block) enables good heat discharge for thevalve apparatus (in particular for the magnet assembly). The heatdischarge into the housing (i.e. into the hydraulic block has a furtheradvantage: in winter, the brake fluid is preheated at the pump, thisleads to improved dynamics of the valve as a result of a rapid pressurebuild-up in winter. Simplified mounting of the hydraulic unit canfurthermore be enabled as a result of this. This leads to cost savings.A calibration/adjustment of hydraulic and magnetic force tolerances isalso advantageously achieved by only one assembly. This leads to anincrease in functional precision and reproducibility and thus functionalimprovement. Extensive advantages also arise in the peripheral anddirect environment. A simplification of the structure of the controlunit is thus enabled, for example, as a result of an integration of thevalve apparatus into the hydraulic block. This is also associated withcost savings. Moreover, as a result of this design, thermal measures inthe control unit for the discharge of heat (and thus also to reducecosts) can be omitted.

In one advantageous embodiment, the hydraulic unit is characterized inthat the valve apparatus is integrated at least partially, in particularfully into the hydraulic block.

As already stated, the valve apparatus comprises the component groupsmagnet assembly and hydraulic cartridge. It should correspondingly beunderstood that one of the two component groups or both are partiallyintegrated into the hydraulic block. It is advantageously alternativelyprovided that both component groups are fully integrated into thehydraulic block. A simple functional connection to the fluid ducts ofthe hydraulic block and/or to a pump group acting into the hydraulicblock can in particular be enabled as a result of the integration of thehydraulic cartridge. The advantages of the integration of the magnetassembly in the hydraulic blocks is—as already stated—e.g. the heatdischarge and e.g. the consequently optimized dynamics of the valve inthe case of cold temperatures.

In one possible configuration, the hydraulic unit is characterized inthat the magnet assembly is retained by direct means, in particularcaulking, in the hydraulic block.

This refers to the fact that a direct connection can be formed or isformed between the magnet assembly and the hydraulic block. For example,a direct caulking of the structural unit of the magnet assembly with thehydraulic block occurs. The entire valve apparatus can be anchored onthe hydraulic block by means of this connection. A simplified mountingof the components can advantageously be carried out.

In one preferred embodiment, the hydraulic unit is characterized in thatthe hydraulic cartridge is retained by means of the magnet assembly inthe hydraulic block.

This refers to the fact that there is a connection between the componentgroups of the valve apparatus hydraulic cartridge and the magnetassembly. The valve apparatus is furthermore fixed in the hydraulicblock by means of the magnet assembly. The hydraulic cartridge is thusalso fixed in the hydraulic block via the magnet assembly. Of course,further means can ensure, for example, precise positioning of thehydraulic assembly or providing it with support such as, for example,protrusions and/or bearing surfaces in the hydraulic block includingpressing in. However, the otherwise frequently used caulking of thehydraulic cartridge with the hydraulic block for fastening the valveapparatus can be dispensed with in this design. As a result of this, asimplified structure and optimized mounting can advantageously beenabled.

In one alternative further development, the hydraulic unit ischaracterized in that the magnet assembly is integrated into thehydraulic block in such a manner that a laminar thermal transmissionfrom the magnet assembly to the hydraulic block is enabled.

This refers to the fact that, for example, a cylindrical recess isprovided in the hydraulic block, into which recess a cylindrical magnetassembly can be integrated. As a result of this, optimized heattransmission can be enabled.

In one advantageous configuration, the hydraulic unit is characterizedin that the magnet assembly bears substantially in a gap-free manneragainst the hydraulic block.

This refers to the fact that the recess in the hydraulic block as wellas the form and dimension of the magnet assembly are matched to oneanother in such a manner that there is a defined fit in the installedstate. The fit enables, for example, the cylindrical magnet assembly andthe cylindrical recess to bear flat against one another. This gap-freefit formation has been shown to be a simple structural measure forimplementing optimized heat transmission.

In one possible embodiment, the hydraulic unit is characterized in thata thermal transition between the magnet assembly and the hydraulic blockis formed by means of two defined, thermally conducting materials, inparticular metals.

This refers to the fact that e.g. the hydraulic block as well as anouter housing part of the magnet assembly are composed of metal and thusimproves heat transfer. Good thermal conduction can be enabled by themetallic transition as a result of the integration of the magnet coilinto the hydraulic block. This enables an improvement in the functioningof the hydraulic unit, in particular in case of cold temperatures.

In one preferred embodiment, the hydraulic unit is characterized in thata thermal conductivity-optimizing medium is incorporated between themagnet assembly and the hydraulic block.

This refers to the fact that e.g. a heat-conducting paste fills a cavitybetween the magnet assembly and the hydraulic block. For this purpose,for example, the heat-conducting paste can be applied on the inside ofthe recess of the hydraulic block and/or the outside of the magnetassembly prior to mounting. In one alternative embodiment, the cavitycan be sprayed out even after mounting. A positive effect on thermaltransmission can advantageously be achieved as a result of this measurewith only little extra outlay.

In one possible further development, the valve apparatus for a hydraulicunit is characterized in that the valve apparatus is configured as apremountable assembly.

This refers to the fact that components and component groups of thevalve unit are configured so that a separately operable assembly (“valveunit”) can be mounted from this. The component groups are therefore notonly joined together during final assembly, rather this can already becarried out at an earlier point in time.

This configuration of the invention can therefore also be understoodsuch that a hydraulic unit with a valve apparatus is provided, whereinthe valve apparatus is formed as a premountable assembly. As a result ofthis, the complexity of mounting can be advantageously simplified. Aseparation of several mounting steps to form coherent units is alsopossible. As a result of this, a cost reduction can advantageously beenabled.

According to the invention, a control unit for a hydraulic unit isfurthermore provided which is characterized in that the control unitcomprises a control for the magnet assembly.

This refers to the fact that the control unit is configured to enable anactuation of the magnet assembly. In particular, the magnet coil is tobe understood as a magnet assembly. In this sense, the hydraulic unitcomprises a control unit, wherein the control unit enables an actuationof the valve apparatus—in particular of the magnet assembly. As a resultof this, a functional integration of the actuation directly into thecontrol unit is advantageously produced. A functional separation betweenthe various structural units is, however, advantageously also produced.This enables a compact design of the hydraulic unit and simple mountingthereof.

In one advantageous embodiment, the control unit for a hydraulic unit ischaracterized in that the control unit is connected directly to thehydraulic block, in particular without spatially accommodating themagnet assembly or encompassing the magnet assembly.

This refers to the fact that the hydraulic unit encompasses both thehydraulic block as well as a control unit. These two structural unitsare joined spatially directly on one another. As a result of this, areduction in the overall installed size is advantageously produced. Itshould furthermore be emphasized that the control unit is configured sothat it does not accommodate the magnet assembly, in particular themagnet coil. The control device therefore does not provide, for example,any recesses into which the magnet coils must or can be inserted. Themagnet assembly or magnet coils are therefore only integrated into thehydraulic block. The control unit covers the magnet coils, however,potentially by bearing against the hydraulic block. As a result of this,a narrow control unit and a reduction in the overall structural volumeof the hydraulic unit are advantageously produced.

In one preferred further development, the control unit for a hydraulicunit is characterized in that a side of the control unit which bearsagainst the hydraulic block is substantially flat and in particular hasno recesses for accommodating the magnet assembly.

This refers to the fact that the control unit does not contain anyopenings into which the magnet assembly, in particular the magnet coilis integrated. The hydraulic unit therefore contains a control unit,wherein a side of the control unit which bears against the hydraulicunit is substantially flat, and in particular has no recesses foraccommodating the magnet assembly. As a result of this, a simplestructure of the control unit is advantageously produced. Moreover, as aresult of the omission of the thermal input by the magnet coil, no heatdissipation measures (and/or thermal measures) in the control unit fordischarging heat are required. As a result of this, a lower cost controlunit is produced. Cost savings furthermore also arise as a result of thesimplification of the structure of the control unit.

EMBODIMENTS

It should be pointed out that the features listed individually in thedescription can be combined with one another in any desired, technicallyexpedient manner and highlight further configurations of the invention.Further features and expediency of the invention will become apparentfrom the description of exemplary embodiments on the basis of theenclosed figures.

In the figures:

FIG. 1 shows a schematic sectional view of one embodiment of a valveapparatus of the hydraulic unit according to the invention; and

FIG. 2 shows a semi-transparent representation of one embodiment of ahydraulic unit according to the invention from two viewing directions.

FIG. 1 shows a schematic side view of a valve apparatus 101 for ahydraulic unit 100 for a vehicle. Valve apparatus 101—also referred toas a solenoid valve in the represented embodiment—comprises the twocomponent groups magnet assembly 1 and hydraulic cartridge 2. Valveapparatus 101 has a housing in which it is positioned and retained. Thishousing is formed by hydraulic block 102. Valve apparatus 101 isintegrated fully into hydraulic block 102 which has a receiving opening3 in the manner of a stepped bore. Valve apparatus 101 inserted intoreceiving opening 3 has a first valve sleeve 4 in which a pole core 5 isarranged in a fixed manner and a solenoid armature 6 is arranged in anaxially displaceable manner. A pressure spring 7, in the present case inthe manner of a helical spring, is provided between pole core 5 andsolenoid armature 6, which pressure spring 7 pushes solenoid armature 6in the direction of a second valve sleeve 8. Second valve sleeve 8 issubstantially mug-shaped, with a side wall 9 and a base 10. Athrough-flow opening 11 is formed in base 10, to which through-flowopening 11 a valve seat 12 is assigned. Solenoid armature 6 bears at itsend facing valve sleeve 8 a closing body 13 which is formed in thepresent case as a sealing ball. Closing body 13 is pushed into valveseat 12 by pressure spring 7 via solenoid armature 6 so thatthrough-flow cross-section 11 is closed.

That end of second valve sleeve 8 which is opposite base 10 faces awayfrom solenoid armature 6 and is guided in first valve sleeve 4. This hasa tapered axial portion 14 in which second valve sleeve 8 is retained ina radially tightly bearing, frictional manner. Where applicable, a weldconnection between the first and second valve sleeve can also beprovided in axial portion 14. First valve sleeve 4 has a region betweenaxial portion 14 and base 10, which region runs radially spaced apartfrom valve sleeve 8, wherein, in this region in valve sleeve 4, severaloutflow openings 15 are arranged distributed over the circumference ofvalve sleeve 4. As a result of the radial spacing of valve sleeve 4 inthe region of outflow openings 15, these are in fluidic connection withthrough-flow opening 11 in so far as closing body 13 was pulled bydisplacement of solenoid armature 6 counter to the spring force ofpressure spring 7.

To this end, valve apparatus 101 has a magnet assembly 1 which is alsoarranged in receiver 3. Magnet assembly 1 comprises a magnet coil 17which is arranged coaxially to valve sleeve 4 and in particular bearingagainst it. Magnet coil 17 extends beyond the free end of valve sleeve4, wherein in turn in particular the pole core projects beyond magnetcoil 17. Magnet assembly 1 is assigned a housing part 18 whichencompasses magnet coil 17. A radially internal portion of housing part18 is formed as stop 19 here, which stop 19 axially acts upon valvesleeve 4 at its free end. As a result, valve sleeve is pushed intohousing 2 and retained therein via housing part 18.

A permanent magnet 16 is furthermore provided which is connected tosolenoid armature 6. For this purpose, solenoid armature 6 has at itsend side facing pole core 5 a magnet receiver which receives permanentmagnet 16. In the exemplary embodiment represented, permanent magnet isembodied as a circular perforated disc through which pressure spring 7engages. Permanent magnet 16 can alternatively be embodied as a squareperforated plate. Permanent magnet 16 enables a balancing out for amagnetic loss of force which arises in the case of small solenoid valvesintegrated into the hydraulic block. In order to open the valve, magnetassembly 1 is energized in the course of an opening process with a firstcurrent direction which generates a magnetic field. This causes polecore 5 and solenoid armature 6 to be attracted with permanent magnet 16so that the air gap between solenoid armature 6 and pole core 5 isreduced and closing body 13 is lifted out of valve seat 12.

It is alternatively naturally also conceivable that the magnetic forceof permanent magnet 16 is predefined so that, in order to open valveapparatus 101, permanent magnet 16, during the opening movement, movessolenoid armature 6 in the direction of pole core 5 if the pressurelocked up in valve apparatus 101 falls below a predefinable thresholdvalue so that closing body 13 is lifted out of valve seat 12.

As a result of the use of permanent magnet 16, a bistable solenoid valvecan also be created. In this case, it is not only in the case of a firstenergization of magnet assembly 1 counter to the spring force of spring7 that permanent magnet 16 supports the opening of valve apparatus 101by means of its magnetic attraction to pole core 5. In the opened state,armature 6 is furthermore retained via permanent magnet 16 on pole core5. An opposite energization of magnet assembly 1 subsequently leads torenewed closing of the valve as a result of a repulsion of solenoidarmature 6 with permanent magnet 16 by pole core 5. Pressure spring 7(as well as the pressure locked in) subsequently holds the valve closedafter removal of energization.

In a further alternative, not represented, valve apparatus 101 can alsobe embodied without pressure spring 7.

In a region 20 on that side of outflow openings 15 opposite axialportion 14, valve sleeve 4 furthermore preferably has a diameter whichforms together with the inner diameter of receiver 3 a press fit so thatvalve sleeve 4 is retained pressed in housing 2 in region 20, as aresult of which on one hand a secure fixing and on the other hand asealing by the pressing connection are ensured. At the same time, theforce of the pressing connection acting radially on valve sleeve 4ensures that axial portion 14 is pressed securely against valve sleeve 8or its shell wall 9.

In order to lock magnet assembly 1 in receiver 3, it is provided thathydraulic block 102 is caulked at the edge of receiver 3 forform-fitting locking of magnet assembly 1 and thus of the entire valveapparatus. Magnet assembly 1 is thus pushed into receiver 3 by caulking21 a or 21 b, as a result of which valve sleeve 4 is pressed intohydraulic block 102 by means of housing part 18 and stop 19. In thiscase, FIG. 2 shows two alternatives: on the left half, a rollingcaulking 21 a and, on the right half, a force-reducing tumbling caulking21 b. In the region of outflow openings 15, hydraulic block 102 has atleast one first fluid port 22 which is fluidically connected to outflowopenings 15 so that hydraulic medium correspondingly reaches through theoutflow opening into the fluid port(s). Hydraulic block 102 furthermorehas a further fluid port 23 in the elongation of valve sleeves 4 and 8which is directly fluidically connected to throughflow-opening 11. Inthe event of activation of the valve, for example, a fluid can thentravel in the direction of arrow 24 from fluid port 23, throughthroughflow-opening 11, into outflow openings 15 to fluid port 22.

A semi-transparent representation of one embodiment of a hydraulic unit100 according to the invention is shown from two viewing directions inFIG. 2. Hydraulic unit 100 comprises the component groups valveapparatus 101, hydraulic block 102, control unit 103 and pump group 104.In this case, hydraulic block 102 is represented to be transparent andhighlights that valve apparatuses 101 are fully integrated structurallytherein. It is apparent that both magnet assembly 1 and hydrauliccartridge 2 lie within hydraulic block 102. It also becomes clear thatall valve apparatuses 101 are integrated into hydraulic block 101. Theright-hand representation furthermore shows four wheel ports 25.

1. A hydraulic unit for a hydraulic brake system, the hydraulic unitcomprising: a hydraulic block; and at least one valve apparatuscomprising: a hydraulic cartridge with a valve seat and a displaceableclosing body configured to block and release the valve seat; a magnetassembly with a magnet coil configured to generate a magnetic force thatdisplaces the closing body, the magnet assembly being integrated intothe hydraulic block; and a permanent magnet configured to assist thedisplacement of the closing body via the magnetic force.
 2. Thehydraulic unit as claimed in claim 1, wherein the valve apparatus isintegrated at least partially into the hydraulic block.
 3. The hydraulicunit as claimed in claim 1, wherein the magnet assembly is retained inthe hydraulic block by a direct connection.
 4. The hydraulic unit asclaimed in claim 1, wherein the hydraulic cartridge is retained in thehydraulic block by the magnet assembly.
 5. The hydraulic unit as claimedin claim 1, wherein the magnet assembly is integrated into the hydraulicblock in such a manner that a laminar thermal transmission from themagnet assembly to the hydraulic block is enabled.
 6. The hydraulic unitas claimed in claim 1, wherein the magnet assembly bears substantiallyin a gap-free manner against the hydraulic block.
 7. The hydraulic unitas claimed in claim 1, wherein a thermal transition between the magnetassembly and the hydraulic block is formed by two defined, thermallyconducting materials.
 8. The hydraulic unit as claimed in claim 1,wherein a thermal conductivity-optimizing medium is arranged between themagnet assembly and the hydraulic block.
 9. A valve apparatus for ahydraulic unit as claimed in claim 1, wherein the valve apparatus isconfigured as a premountable assembly.
 10. A control unit for ahydraulic unit of a hydraulic brake system, the hydraulic unit includinga hydraulic block and at least one valve apparatus that includes (i) ahydraulic cartridge with a valve seat and a displaceable closing body,(ii) a magnet assembly with a magnet coil configured to generate amagnetic force that displaces the closing body, the magnet assemblybeing integrated into the hydraulic block, and (iii) a permanent magnetconfigured to assist the displacement of the closing body bia themagnetic force, the control unit comprising: a control configured tocontrol the magnet assembly.
 11. The control unit as claimed in claim10, wherein the control unit is connected directly to the hydraulicblock.
 12. The control unit as claimed in claim 11, wherein a side ofthe control unit which bears against the hydraulic block issubstantially flat.
 13. The control unit as claimed in claim 11, whereinthe control unit is connected directly to the hydraulic block withoutspatially accommodating the magnet assembly or encompassing the magnetassembly.
 14. The control unit as claimed in claim 12, wherein the sideof the control unit which bears against the hydraulic block has norecesses for accommodating the magnet assembly.
 15. The hydraulic unitas claimed in claim 2, wherein the valve apparatus is fully integratedinto the hydraulic block.
 16. The hydraulic unit as claimed in claim 3,wherein the magnet assembly is retained in the hydraulic block bycaulking.
 17. The hydraulic unit as claimed in claim 7, wherein the twodefined, thermally conducting materials are metals.